CN101889387A - Circuit for controlling the current in an electrical control member or the voltage across the terminals of the said electrical control member - Google Patents

Abstract

The present invention relates to a circuit (300) for controlling the current in an electrical control member (110) comprising a bridge furnished with four terminals (105, 106, 107, 108) and comprising four controlled breakers (AH, AL, BH, BL), a power supply (109), means of control by MLI of at least two of the four breakers. The control circuit exhibits a first state in which said first (AH) and fourth (BL) breakers are closed and said second (BH) and third (AL) breakers are open, a second state in which said second (BH) and third (AL) breakers are closed and said first (AH) and fourth (BL) breakers are open and at least one of the two following states: a third state in which said third (AL) and fourth (BL) breakers are closed and said first (AH) and second (BH) breakers are open and/or a fourth state in which said first (AH) and second (BH) breakers are closed and said third (AL) and fourth (BL) breakers are open. A particularly interesting application of the invention lies in the field of controlling the current of the actuators used for 'camless' systems in motor vehicles.

Description

Be used for controlling the electric current of electric control unit or the circuit of the voltage between its terminal

Technical field

The present invention relates to be used for to control the circuit of the voltage between the terminal of the electric current of electric control unit or described electric control unit.Significant especially application of the present invention is Control current or has the field of the motor of variable inductance (such as the actuator that is used for the so-called electromagnetically operated valve of motor vehicles (" no cam " system)).

Background technology

The Electromagnetically actuated electric energy that needs of electromagnetically operated valve.This electric energy comes from the In-vehicle networking on the motor vehicle.The performance of solenoid valve system relates to the power consumption that minimizes on the onboard networks.In practice, the available power of output place of arbor equals the power that the real gross power of sending out of hot machine deducts proper operation (driving of the actuating of valve, water and oil pump the or the like) needs of its servicing unit.

Usually, by the control of the power bridge of H structure, the power bridge of this H structure is also referred to as " four-quadrant " electric bridge (or " full-bridge chopper (chopper) ") to the motor of plus or minus Current Control usually, and it is single-phase or heterogeneous according to the structure of this motor.Term " four-quadrant " electric bridge is appreciated that and means the electric bridge control of working on the All Quardrants of voltage-current characteristic.Usually, the control of PWM (pulse width modulation) type of this control electronic equipment by will having fixed frequency puts on power bridge and forces electric current to set point.The example of the electronic structure of " four-quadrant " electric bridge 1 has been shown among Fig. 1.Electric bridge 1 comprises:

-four terminals 5,6,7 and 8,

-be connected to first and second terminals 5 of electric bridge 1 and 6 dc voltage source 9 (this for example can be battery, DC-DC power supply changeover device or AC-DC power supply changeover device),

-electric control unit 10 (such as the electric loading with variable inductance) is used to control actuator and is connected between third and fourth terminal 7 and 8 of bridge circuit 1,

-be connected the first switch C between the first and the 3rd terminal 5 and 7 ₁,

-be connected the second switch C between the first and the 4th terminal 5 and 8 ₂,

-be connected the 3rd switch C between the second and the 3rd terminal 6 and 7 ₃,

-be connected the 4th switch C between the second and the 4th terminal 6 and 8 ₄

Therefore, electric bridge 1 comprises respectively by the switch C that connects ₁And C ₃And by the switch C that connects ₂And C ₄Two arm B1 that form and B2.

Mains switch C ₁And C ₄Can be MOSFET (mos field effect transistor) transistor or IGBT (insulated gate bipolar transistor) transistor.

The technology that the most generally is used for its robustness is by pulse width modulation (PWM) average current to be controlled in the control of switch by using.Its great advantage is its immunity to noise.In practice, regulating loop does not need transient current but through the value of filtering.Delay has been introduced in this filtering, and this delay can prove limitation in height when pursuing high bandwidth.Under the situation of " no cam " system actuator, the value watch-dog calculates the voltage set point V of the terminal that must be applied in magnetic circuit ^*The pulse width modulation strategy converts voltage set point to the instruction of the electronic switch (in this case, for them four) of closure/deenergization electronic equipment.The constraints (management of Dead Time, complete time etc.) that the order of power electronics application PWM strategy is observed it simultaneously.If Sc _iBe used to represent switch C _iSwitch function, then we obtain:

Two switch (C for same bridge arm _iAnd C _I+2) control be the opposition to avoid causing power supply short circuit.Thereby given two switch functions (one on each arm) trend in time is enough to according to dc voltage U _DCDetermine the voltage U at the terminal place of magnetic circuit 10 _ActFor convenience's sake, select the switch function of high switch usually.Disconnect and closing time by voltage drop and the switch of ignoring in the conducting element, can release following formula:

U _act＝(Sc ₁-Sc ₂)U _DC

For simply, by with standardized voltage set point v ^*Value and frequency f _PWMSingle triangular carrier V _p(t) relatively come to determine switch function Sc ₁And Sc ₂Time trend.Trigonometric function can be to get minimum value V _PminWith maximum V _PmaxBetween any function of value.Standardized set-point voltage v ^*Value be then:

$v^{*}=\frac{V_{p\max }-{\mathrm{<figure-callout\; id="2"\; label="V\; p\; min"\; filenames="HPA00001151583800172.png"\; state="\{\{state\}\}">V</figure-callout>}}_{p\min }}{2.U_{\mathrm{DC}}}.(V^{*}-U_{\mathrm{DC}})+V_{p\max }$

By by following formula defined function symbol (x):

Switch function Sc ₁(t) be confirmed as:

Sc ₁(t)＝sign(v ^*-V _p(t))

Function S c ₂(t) be Sc ₁(t) complementary function, it also can be calculated by following formula:

Sc ₂(t)＝sign(V _p(t)-v ^*)

Fig. 2 diagrammatic representation switch function Sc ₁(t) and Sc ₂Determining (t).Thereby the first curve representation trend is as standardized set-point voltage v ^*Time and triangular carrier V _p(t) function.Thus, release the Sc of expression as the function of time ₁Second curve of trend and expression as the Sc of the function of time ₂, with the 3rd curve of the second curve complementation.Voltage U between the terminal of the 4th curve representation magnetic circuit 10 _ActTrend, this voltage is at+U _DCWith-U _DCBetween change, and at copped wave time period f _PWMOn have mean value V ^*Because voltage U _ActCan only get two different values, so this is called as bifurcation PWM strategy.

Fig. 3 shows on the four-quadrant electric bridge 11 that comprises respectively four switch AH, BH, AL and the BLs identical with transistor C2, C1, C4 and the C3 of electric bridge 1 shown in Figure 1 the conversion that causes for to the control of load 10 and by this class PWM strategy.

Electric bridge 11 has two possible states:

-magnetized state (voltage V _L=+U _DCPut on actuator), wherein switch BH and AL closure, switch AH and BL disconnect,

-demagnetizing state (voltage V _L=-U _DCPut on actuator), wherein switch BH and AL disconnect, switch AH and BL closure.

But, realize that for the four-quadrant electric bridge such PWM control can produce some difficulty.

First difficulty relates to switching loss.When switch changes state (from be disconnected to closed conversion or from being closed into the conversion of disconnection) because by its electric current with exist the voltage at its terminal place the time and cause loss.The energy of Hao Saning depends on dc voltage U then _DCValue, chopper current I _ActValue and the value of switch speed (switching time is for example by the value setting of the gate resistance of the mosfet transistor that uses).Thereby, for each copped wave time period, there are twice disconnection and twice closure, no matter the sense of current on the switch in two switches of each electric bridge length is how.This pair of switching of each copped wave time period obviously causes loss, and it is big that this loss becomes along with the increase of frequency.Note, efficient and bandwidth are coordinated.Under the situation of PWM control, the PWM frequency is typically tens and even hundreds of KHz.When these high-frequencies, switching loss than other conduction loss in the highest flight.Note, in the conversion from the magnetized state to the demagnetizing state of four handover operations of each copped wave time period, two is the direct-cut operation operation, two is operating in soft handover: in other words, the first step is two transistors (direct-cut operation) that disconnect closure when initial, then after Dead Time, two initial transistor closures (soft handover) that disconnect.Thereby avoided two switches in the same arm closed simultaneously.At (before soft handover) during the Dead Time, the diode of switch mosfet inside (being called " afterflow ") conduction, thereby the feasible MOSFET electromotive force that can keep during soft handover approaches zero.

In addition, the switching of repetition not only influences the efficient of control electronic equipment, and influences the efficiency of motor that they drive.The copped wave of voltage produces high-frequency harmonic, and this causes the loss of motor.These motors are usually by the magnetic material of supporting vortex flow (iron-Si) constitute for example.This induction produces induced voltage in pole plate, this induced voltage produces usually significant vortex flow according to the resistivity of pole plate.Although pole plate is cut subtly and be insulated from each other, the electric current of Liu Donging produces loss by Joule effect therein.As mentioned above, the 4th curve representation of Fig. 2 has value U _DCThe situation of voltage source 9 under voltage U between as shown in Figure 1 the terminal of load 10 _ActThe control of electric bridge is to have the PWM type that occupation efficiency is α.Voltage U _DCBe applied in load 10, ignore because the voltage drop that the resistance of switch causes.No matter what occupation efficiency is, if the latter is a constant, then puts on the effective value (U of the voltage of load 10 _Eddy) equal voltage U _DC(it represents voltage U _ActCrest voltage): U _Eddy=U _DCAt last, by its frequency be higher than chopping frequency and for its loss that can consider that the vortex flow of constant occupation efficiency produces proportional with crest voltage basically: P _Eddy=k.U _Eddy=k.U _DC

In addition, electronic equipment particularly the control of their switch owing to copped wave produces high frequency common mode current.Load generally has the capacitive couplings with respect to ground.For example, under the situation of coiling electric motor, at the winding that is subjected to common-mode voltage be linked between the frame on ground and have significant coupling.Thereby the generation common mode current, and they form the loop by power supply.These high-frequency current loops cause electromagnetic radiation, and this electromagnetic radiation has influence aspect current EMC (Electro Magnetic Compatibility) standard meeting.

Summary of the invention

Under this background, the present invention seeks to be provided for controlling " four-quadrant " bridge circuit of the voltage between the terminal of electric current in the electric control unit or described control assembly, described circuit provides the switching loss that reduces in the mains switch, reduces loss relevant with the vortex flow in the magnetic circuit and the mode of avoiding the economy of above-mentioned EMC problem.

For this reason, the present invention proposes the circuit of the voltage between the terminal of a kind of electric current that is used for controlling electric control unit or described electric control unit, described circuit comprises:

-electric bridge provides four terminals and comprises four control switchs,

-be used for the power supply of described electric bridge,

-utilize pulse width modulation to control the device of at least two switches in described four switches,

Described power supply is connected between the first terminal and second terminal of described electric bridge,

Described electric control unit is connected between the 3rd terminal and the 4th terminal of described electric bridge,

Described first switch is connected between the described the first terminal and described the 3rd terminal of described electric bridge,

Described second switch is connected between the described the first terminal and described the 4th terminal of described electric bridge,

Described the 3rd switch is connected between described the 3rd terminal and described second terminal of described electric bridge,

Described the 4th switch is connected between described the 4th terminal and described second terminal of described electric bridge,

Described control circuit is characterised in that it presents:

-the first state, the wherein said first and the 4th switch closure, and the disconnection of the described second and the 3rd switch,

-the second state, the wherein said second and the 3rd switch closure, and the disconnection of the described first and the 4th switch,

In-following two states at least one:

Zero third state, wherein said third and fourth switch closure, and the disconnection of described first and second switches,

Zero four condition; Wherein said first and second switch closures; And described third and fourth switch disconnects;

The mandate of described pulse width modulation control device:

-from described first state to the described the 3rd or four condition the transformation of at least one state,

-from described second state to the described the 3rd or four condition the transformation of at least one state,

-from the described the 3rd or four condition at least one state to the transformation of described first state,

-from the described the 3rd or four condition at least one state to the transformation of described second state.

According to the present invention, this control circuit can be used to manage three or one of four states (that is, this circuit can be used to switch to three or four different states) by " four-quadrant " electric bridge of PWM policy control.The PWM strategy that proposes is called as ternary, because put on the voltage V of the terminal of load (electric control unit) _LBe based on three level :-U _DC, 0 and U _DC(wherein, U _DCThe voltage that appointment is supplied with by power supply).A direct-cut operation (with a soft handover) has been saved in the introducing of the third state.For fear of the direct transformation between " magnetization " state that causes two direct-cut operations and " degaussing " state, allow in a circuit according to the invention from " magnetization " state to so-called " afterflow " state (corresponding to the 3rd or four condition any one) transformation and transformation from " degaussing " state to " afterflow " state.Therefore, the number of switching can reduce half.Such minimizing has remarkable influence to the size of power electronics, and allows:

The raising of the reliability of-existing power supply electronic equipment;

The miniaturization of the assembly of-use;

The reduction of-cost.

In addition, about loss by vortex flow, the control of the routine of the four-quadrant electric bridge that electric bridge is switched to two states with electric bridge between the control of the proposition according to the present invention of switching between three or the one of four states, effective value differs greatly.Ternary or four attitudes control applies less voltage and controls identical electric current, and in other words identical average voltage is provided.

In addition, as mentioned above, has parasitism (spurious) electric capacity with respect to frame by the actuator of electric component controls.The copped wave of voltage produces high-frequency harmonic in the control electronic equipment, it returns via ground.These are common mode disturbances.This noise level of EMC criteria limit.According to the present invention, the voltage that is produced by three-state control produces the harmonic wave that lacks than bifurcation control.Thereby realize that common mode current reduces 6dB.

Can also present one or more (considering individually or with all technical possible combinations) in the following feature according to system of the present invention.

Advantageously, described pulse width modulation control device mandate:

-the first so-called negative alternating phases, comprise transformation and transformation from the described third state to described first state from described first state to the described third state, the described first and the 3rd switch forms the first arm, be called the amplitude arm, switch with so-called chopping frequency, and the described second and the 4th switch forms second arm, be called the symbol arm, the described second and the 4th switch is closed and disconnected respectively

-the second so-called just alternately stage, comprise transformation and transformation from described four condition to described second state from described second state to described four condition, the described first and the 3rd switch switches with described so-called chopping frequency, and the described second and the 4th switch disconnects respectively and closure

The switching of described second and the 4th switch of described symbol arm guarantee described negative alternately and just alternately to be lower than the frequency transitions of described chopping frequency.

Advantageously, control circuit according to the present invention comprises the bypassed resistor that is connected in series between described electric control unit and described the 4th terminal.

In this case, this control circuit preferentially comprises operational amplifier, and the terminal of described bypassed resistor forms the anti-phase and in-phase input end of described operational amplifier.

Advantageously, control circuit according to the present invention comprises:

-charge pump capacitor, when being recharged, it is suitable for transmitting the control voltage that is used for described second switch;

-second source transmits the voltage less than the voltage that is transmitted by described first voltage source, and described second voltage source is applicable to that be described charge pump capacitor charging when described the 4th switch closure;

-be used for when described control circuit just is in stage alternately, forcing transformation so that the device that described charge pump capacitor is recharged via described second source from described four condition to the described third state.

According to first embodiment, described control device comprises:

-be used to produce and have the device that occupation efficiency is the pulse width modulating signal of α;

-be used for described that to have occupation efficiency be that the pulse width modulating signal of α is applied to described the 3rd switch and will has occupation efficiency is the device that the pulse width modulating signal of 1-α is applied to described first switch;

-be used for just alternately and between negative the replacing having enough to meet the need to realize the device of following state machine:

Zero when described electric bridge be in it just alternately and occupation efficiency α when being eliminated, this state machine detected state changes and changes into alternately negative.

Zero when described electric bridge be in it negative alternately and occupation efficiency α when equaling 100%, this state machine detected state changes and just changes into and replaces.

Advantageously, described power delivery dc voltage+U _DC, described control circuit comprises:

-be used for will equaling product α * U during just alternately described _DCAverage voltage be applied to the device of described electric control unit;

-be used for during described negative replacing, will equaling product (α-1) * U _DCAverage voltage be applied to the device of described electric control unit.

According to second embodiment, described control device comprises:

-be used to produce and have the device that occupation efficiency is the pulse width modulating signal of α;

-be used for described pulse width modulating signal with occupation efficiency α convert to have occupation efficiency be α '=| the device of the pulse width modulating signal of 2 α-1|;

-be used for described that to have occupation efficiency be that the pulse width modulating signal of α ' is applied to described the 3rd switch (AL) and will has occupation efficiency is the device that the pulse width modulating signal of 1-α ' is applied to described first switch (AH) with described during just alternately;

-be used for described that negative to have occupation efficiency be that the pulse width modulating signal of 1-α ' is applied to described the 3rd switch (AL) and will has occupation efficiency is the device that the pulse width modulating signal of α ' is applied to described first switch (AH) with described during alternately;

-be used for just alternately and negative alternately between by to realize the device of following state machine:

Zero when described electric bridge be in it just alternately and described occupation efficiency α strictness less than 50% the time, described state machine detected state changes and changes into alternately negative.

Zero when described electric bridge be in it negative alternately and described occupation efficiency α more than or equal to 50% the time, described state machine detected state changes and just changes into and replaces.

Advantageously, described power delivery dc voltage+U _DC, described control circuit comprise be used for described just alternately during and negatively will equal product (2 α-1) * U during alternately described _DCAverage voltage be applied to the device of described electric control unit.

Advantageously, described be used for described pulse width modulating signal with occupation efficiency α convert to have occupation efficiency be α '=| the device of the pulse width modulating signal of 2 α-1| comprises:

-be used to carry out the device that occupation efficiency equals the subtraction between the described signal that 50% signal and occupation efficiency be α;

-be used for the device that will double by the signal that described subtraction obtains.

Preferentially, described to be used to carry out the device that occupation efficiency equals the subtraction between the signal that 50% signal and described occupation efficiency be α be the device of carrying out the XOR function, and having described occupation efficiency on its two inputs respectively, to equal 50% signal and described occupation efficiency be the signal of α.

Preferentially, the described device that is used for being doubled by the signal of described subtraction acquisition comprises at least one counter.

Advantageously, described control device is included in the Programmable Logic Device.

Advantageously, described switch is a mosfet transistor.

Another theme of the present invention is the purposes of control circuit according to the present invention in the electric parts that formed by the inductive load with variable inductance.

Advantageously, these electricity parts are included in to have in the actuator that activates part, and described electric parts are controlled described actuating part with displacement mode.

Preferentially, described actuator is the electromagnetic valve actuator that is used for motor vehicles.

Description of drawings

Other features and advantages of the present invention will be from following description, via indication and non-limited way, with reference to the accompanying drawings and clear presenting, wherein:

-Fig. 1 is that the rough schematic view of electronic structure that the four-quadrant electric bridge of prior art is shown is represented;

The switch function Sc of the switch of-Fig. 2 diagrammatic representation four-quadrant electric bridge as shown in Figure 1 ₁(t) and Sc ₂Determining (t);

-Fig. 3 illustrates the switching that is caused by the PWM strategy according to prior art on the four-quadrant electric bridge;

-Fig. 4 illustrates the state according to the control circuit of the first embodiment of the present invention;

-Fig. 5 and 6 illustrates respectively under according to the situation of the PWM control of two states of use of prior art and puts on the voltage of load (such as the load of Fig. 4) and the electric current in this load trend as the function of time under the situation of the control circuit of three states of use according to the present invention;

-Fig. 7 represents to be used for the circuit of direct sensing lead electric current;

-Fig. 8 represents the state of control circuit according to a second embodiment of the present invention;

-Fig. 9 illustrates the state of control circuit of a third embodiment in accordance with the invention of merge pass resistor;

-Figure 10 illustrates the electric current of measurement of circuit as shown in Figure 9 and the load current trend as the function of time;

-Figure 11 represents to be used for the charge pump circuit according to the switch of control circuit of the present invention;

-Figure 12 represents to be used for the regulating loop according to the control circuit of prior art;

-Figure 13 illustrate according to the regulating loop of Figure 12 use, the structure of the pulse width modulating signal of structure;

-Figure 14 is illustrated in the average voltage of being observed by load under the situation of regulating loop of Figure 12;

-Figure 15 illustrates first embodiment that is used for according to the regulating loop of four condition control circuit of the present invention;

-Figure 16 represents to be used to realize the state machine according to the regulating loop of Figure 15;

-Figure 17 is illustrated in the average voltage of being observed by load under the situation of regulating loop of Figure 15;

-Figure 18 to 21 is illustrated in voltage between the terminal of electric current, current setpoint, pwm signal, mark signal and the load of measuring in the different structure according to the regulating loop of Figure 15 as the function of time;

-Figure 22 illustrates second embodiment that is used for according to the regulating loop of four condition control circuit of the present invention;

-Figure 23 represents to be used for the embodiment of substracting unit of the regulating loop of Figure 22;

-Figure 24 represents to be used for the embodiment of doubler of the regulating loop of Figure 22;

-Figure 25 represents to be used to realize the state machine according to the regulating loop of Figure 22;

-Figure 26 is illustrated in the average voltage of being observed by load under the situation of regulating loop of Figure 15.

Embodiment

In all figure, give public element identical reference number.

With reference to prior art Fig. 1 to 3 is described as above.

Fig. 4 illustrates three states according to control circuit 100 of the present invention.

Circuit 100 comprises:

-four terminals 105,106,107 and 108,

-conveying voltage+U _DCDc voltage source 109, for example battery or DC-DC power supply changeover device (or AC-DC power supply changeover device) are connected to first and second terminals 105 and 106 of electric bridge 1,

-electric control unit 110 such as inductive load, is used to control actuator and is connected between third and fourth terminal 107 and 108,

-be connected the first switch AH between the first and the 3rd terminal 105 and 107,

-be connected the second switch BH between the first and the 4th terminal 105 and 108,

-be connected the second switch AL between the second and the 3rd terminal 106 and 107,

-be connected the 4th switch BL between the second and the 4th terminal 106 and 108.

Mains switch AH, BH, AL and BL for example are mosfet transistors.Each transistor has the diode (presenting straight-through (through) structure under the situation of mosfet transistor) of antiparallel installation.

" arm A " will be used to represent to comprise that the switch AH of series connection and the arm of AL, " arm B " will be used to represent to comprise the switch BH of series connection and the arm of BL hereinafter.

Electric control unit (being also referred to as load hereinafter) 110 is the variable inductance of the actuator (electromagnet) that is used to control electromagnetically operated valve in the case.Variable inductance obviously is not desirable and comprises active component.Electric current in the electric control unit 110 for example is used for the disconnection and the closure (by the flashboard (paddle) that valve is remained on disconnection or make position) of control valve.The position of valve is by the set point definition corresponding with setpoint current.

Figure 4 illustrates three states (being respectively: magnetization, afterflow (freewheeling) and degaussing):

The situation that-magnetized state disconnects corresponding to transistor BH and AL closure and transistor AH and BL: in this case, put on the voltage V of the terminal of load 110 _LHas value+U _DC

The state that-afterflow state disconnects corresponding to transistor AL and BL closure and transistor AH and BH: this state will be called as " low " afterflow state hereinafter, and the another kind of afterflow state (not illustrating here) that is called " height " afterflow state that disconnects with wherein transistor AH and BH closure and transistor AL and BL is opposite.Under the situation of high or low afterflow, put on the voltage V of the terminal of load 110 _LHas value 0.

The situation that-demagnetizing state disconnects corresponding to transistor BH and AL closure and transistor AH and BL: in this case, put on the voltage V of the terminal of load 110 _LHas value-U _DC

The benefit of introducing these three (or four) states is that they provide the mode that reduces the number that switches in each cycle.Transformation from the magnetized state to the demagnetizing state (vice versa) needs twice switching, and the transformation from magnetized state or demagnetizing state to afterflow state (high or low) only needs once to switch.In practice, under first kind of situation, two arms are switches simultaneously, and in another case, only an arm switch.We will see hereinafter that use is hanged down and high two afterflow states are useful; But these two states (height afterflow) are realized identical functions, and also can only use in two afterflow states one: this structure as shown in Figure 4 owing to only used low afterflow state.

In order to save the number of switching, there is not any direct transformation between magnetized state and the demagnetizing state forever.Thereby, for given frequency, can with the decreased number switched half.

Fig. 5 and 6 illustrates respectively under according to the situation of the PWM control of two states of use of prior art and puts on the voltage VL of terminal of load 110 (such as the load of Fig. 4) and the trend of the electric current I L in this load under the situation of the control circuit of three states of use according to the present invention.

As can be seen, under the situation of bifurcation control, in load, keep plus or minus electric current I L cause being operated on two quadrants (corresponding with magnetization and demagnetizing state respectively positive voltage alternately and negative voltage replace+U _DCWith-U _DC), and utilize the identical control of the electric current of three states to make can in fact only to be operated on the quadrant (according to controlled be that positive current or negative current are the plus or minus alternating voltage, and the almost no-voltage corresponding with the afterflow state).

Note, in structure shown in Figure 4, only use low afterflow state, and two arm A and B switch with the frequency of PWM control (common tens and even hundreds of kHz).

Such structure can cause some common mode disturbances that direct load current is measured.We will at first describe the circuit 200 that is used to carry out such measurement with reference to figure 7 briefly.

Circuit 200 is except comprising as above with reference to the figure 4 described assemblies, also comprise the bypassed resistor 201 of connecting with load 110, described bypassed resistor have the terminal 108 that is linked to circuit 200 and operational amplifier 202 in-phase input end terminal 203 and be linked to load 110 and the terminal 204 of the inverting input of operational amplifier 202.

The advantage of when realizing Average Current Control, directly in load, taking current measurement be needn't the reconstruct electric current to obtain the image of average current.In addition, because bypassed resistor is cheap solution, the use of therefore accepting the operational amplifier of high common-mode voltage is important.Thereby, can have measurement result with respect to the ground reference.On the other hand, phase place is subjected to the strong potential change with respect to ground.Why Here it is needs high common-mode rejection ratio (high CMRR) so that have in the output of amplifier measurement result not affected by noise.The filtering of measurement result can reduce common-mode noise, but it also hinders bandwidth or stability.When having high bandwidth and must having when switching fast, may be difficult to have specific measurement result.

Thereby, have the circuit 200 that bifurcation PWM controls by use, because each switching of the switch of the adjusting of disturbance current, thereby the measurement result of electric current is subjected to the noise effect of peak value.

Avoid the solution of this problem to be to organize the order of four possible states (magnetization, degaussing, high afterflow, low afterflow), do not switch with chopping frequency so that be linked to the arm electric bridge (arm B in this case) of current measurement bypassed resistor 201.

This solution as shown in Figure 8, Fig. 8 represents the order of the one of four states of the control circuit 300 that formed by the assembly identical with the assembly of circuit 100 shown in Figure 4.

Below in text, we will distinguish two macrostates of four-quadrant control circuit 300:

-term " just replaces " and is applied to control circuit 300 diverter switch AH, AL, BH and BL so that the average voltage that load 110 is observed is timing.Notice that positive average voltage causes the positive current I in the load _L

-statement " alternately negative " be applied to described control circuit diverter switch so that the average voltage that load 110 is observed when negative.Notice that positive average voltage causes the positive current I in the load _L

By operating rocker A switch AH only with AL and arm B switch always remains on that (BH closure and BL disconnect) obtains just to replace in the identical state; Thereby under situation about just replacing, having transformation from magnetized state (AH disconnects and the AL closure) to high afterflow state (AH closure and AL disconnect), the transformation between these two states is with chopping frequency (common tens and even hundreds of kHz) generation.Thereby during just alternately, only arm A switches with high frequency (chopping frequency), and arm B does not switch.

Obtain from just replacing by operating rocker B (BH disconnects and the BL closure) to negative transformation alternately.

By operating rocker A switch AH only with AL and arm B switch always remains on that (BH disconnects and the BL closure) obtains alternately negative in the identical state; Thereby under negative situation alternately, having transformation from magnetized state (AH closure and AL disconnect) to low afterflow state (AH disconnects and the AL closure), the transformation between these two states is with chopping frequency (common tens and even hundreds of kHz) generation.Thereby during negative replacing, as during just replacing, only arm A switches with high frequency (chopping frequency), and arm B does not switch.

Regardless of magnetizing and ratio between duration of low afterflow state, the average voltage that load 110 is observed is positive.Here it is, and why term " just replaces " switching that is used to specify between these two states.

In the same way, regardless of the ratio between the duration of degaussing and afterflow state, the average voltage that load 110 is observed is born.Here it is, and why term " alternately negative " is used to specify the switching between these two states.

By distinguishing high afterflow and low afterflow, for identical replacing, only control switching circuit 300 arm.

During just alternately, arm B (BH closure, BL disconnects) does not switch, and arm A switches with chopping frequency.Similarly, during negative replacing, arm B (BH disconnects, the BL closure) does not switch, and arm A switches with chopping frequency.

Thereby, these two alternately during, arm B does not switch.The switching of arm B only occurs over just when alternately changing, and the symbol that put on the average voltage of load 110 this moment changes.Two switchings between alternately take place with the frequency that is significantly less than chopping frequency with the frequency of the bandwidth that is lower than Current Regulation, in theory less than 1/2nd of chopping frequency, but generally greater than 1/10th (common several KHz) of chopping frequency.

Therefore, can be (in this case with the arm of electric bridge, be arm A) be exclusively used in high frequency and switch the amplitude (absolute value) that puts on the voltage of load with adjusting, and another arm (in this case, being arm B) is exclusively used in low frequency switches the polarity that puts on the voltage of load with adjusting.

Below in text, differentiation is used for the amplitude arm (arm A) of the amplitude of accommodation and is used to regulate the symbol arm (arm B) of the polarity of the voltage that puts on load.

The use of amplitude arm and symbol arm is for the structure particular importance of the control circuit of merge pass resistor.

The positive and negative of such circuit 400 alternately as shown in Figure 9.Circuit 400 is except comprising the assembly of above describing with reference to figure 4, also comprise the bypassed resistor 201 of connecting with load 110, its have the terminal 108 that is linked to circuit 200 and operational amplifier 202 in-phase input end terminal 203 and be linked to load 110 and the terminal 204 of the inverting input of operational amplifier 202.The arm A that is formed by switch AH and AL is the amplitude arm, and it switches and be used for being provided with the absolute value of the electric current of load 110 with chopping frequency.The arm B is-symbol arm that forms by switch BH and BL and being used to carry out just alternately and negative transformation between alternately.

This structure particular importance is because the generation of common mode disturbances is less than the generation according to the common mode disturbances of the two-layer configuration of prior art.Disturb only occur over just symbol alternately during.Physically, sign modification occurs in the slope (slope) of electric current when reversing basically.Figure 10 shows according to the not operation of demonstration (disembodiment): the electric current I L that measures in voltage VL between the terminal of load and the load (by bypassed resistor 201 and operational amplifier 202) is represented as the function of time.Just alternately AP (BL disconnects and the BH closure during it) back is negative alternately AN (BH disconnects and the BL closure during it).Common mode disturbances (current peak of the electric current of interferometry) only occurs over just when changing alternately.As noted before, utilize bifurcation structure according to prior art, we will observe peak value when each the switching.

It should be noted that, it is alternately closed always with regard to one in two transistors of hold mark arm B that the embodiment that describe with reference to figure 9 and 10 relate to short of change: thereby, under the situation of regulating positive constant current, the control of the closure of the transistor BH of symbol arm can be permanent.For MOSFET or igbt transistor are remained on this closure state, control voltage must be put on its grid.To control voltage puts on a transistorized solution and is to use so-called charge pumping technique.Figure 11 shows the charge pump circuit 500 that is used for according to the switch of control circuit of the present invention, its feasible control voltage (only showing arm B among Figure 11) that can keep on the transistor BH.Circuit 500 comprises:

-accessory power supply 501, delivery ratio come from the voltage U of main power source _DCThe voltage of little (common 12 to the magnitude of 15V, and these magnitudes of voltage are corresponding with the representative value of the grid that is used to control mosfet transistor);

-diode 502, its anode is linked to accessory power supply 501;

-capacitor 503 has the first terminal of the negative electrode that is linked to diode 502 and is linked to second terminal of the public terminal of transistor BH and BL;

-the first switch 504 has the first terminal of the negative electrode that is linked to diode 502 and is linked to second terminal of the grid of transistor BH;

-second switch 505, thus have second terminal that is linked to first switch 504 be linked to transistor BH grid the first terminal and be linked to second terminal of the public terminal of transistor BH and BL.

Come to be capacitor 503 chargings by closed transistor BL via accessory power supply 501.

When switch 504 closures, the capacitor 503 that has charged is carried the voltage of the grid that is used for oxide-semiconductor control transistors BH.

Now, for using charge pumping technique, oxide-semiconductor control transistors BH do not make it possible to keep forever the voltage on the grid to recharge.Thereby, when the duration that is just replacing surpasses sometime (when regulating positive current possible situation), no longer can guarantee the closure of the transistor BH of symbol arm, because the capacitor of charge pump 503 is discharged in the grid of transistor BH gradually.

For fear of the unnecessary disconnection of this MOSFET, solution is to force the closure of transistor BL of symbol arm with the charging of the capacitor 503 that guarantees charge pump.

For fear of interference load control, this transformation will occur in during the high afterflow state (zero average voltage is observed in load), and compulsory state will be low afterflow state (zero average voltage is observed in load).The control of load is not subjected to the interference of such action, because the equivalence fully with respect to load control of high afterflow and low afterflow state.Thereby recharging of charge pump is with respect to the transparent action of load (electric control unit).

Thereby the capacitor 503 of charge pump is recharged, so that keep the enough control voltage on the transistor BH; For this reason, the symbol arm turns back to the control of transistor BL, and its feasible diode 502 by charge pump circuit 500 is recharged capacitor 503 by accessory power supply 501.

We will be described below have one of four states two embodiment of control of (high afterflow wherein and low afterflow state see it is equivalent from the viewpoint of load).

Before describing, we will recall the operation of regulating loop of the bifurcation control of four-quadrant electric bridge briefly; Such loop 600 is presented among Figure 12.Loop 600 comprises:

-subtracter 601;

-amplifier 602;

-have a generator 603 of PWM (pulse width modulation) signal of occupation efficiency α;

-four-quadrant electric bridge 604 is used for chopping voltage is offered load (being generally inductive load) 605, to the electric current I of its measurement _MesFormation will be by the electric current of described loop 600 lockings.

Regulating loop 600 work of the bifurcation control of electric bridge 604 are as follows: with current setpoint I _RefWith the measurement result I that wants blocked electric current _MesCompare.The current setpoint I that determines by subtracter 601 _RefWith the measurement result I that wants blocked electric current _MesBetween poor E be that the amplifier 602 of G amplifies by gain, with the poor Ea (gain G can be the combination of proportional gain, storage gain and the differential gain) that amplification is provided.The error E a that amplifies is compared with carrier wave (amplitude of typically being is triangular wave or the sawtooth signal of A), so that produce pwm signal, its pulse duration is by the error modulation (α is used to represent the occupation efficiency of pwm signal) of amplifying.Dead Time between the closed and disconnected of the switch by observing same arm utilizes the switch of this pwm signal (or signal of utilization and pwm signal complementation) control four-quadrant electric bridge.Therefore, will be with the voltage V of carrier frequency copped wave _LPut on load 605.Put on the average voltage of load 605

Directly depend on occupation efficiency α.Inductance is the electric current I of the load 605 of L _L(wherein, line resistance is ignored) forms (integrate) this voltage.Thereby the electric current in the load can increase with the direction opposite with the variation of the deviation of electric current or set point or reduce.

Figure 13 illustrate according to the regulating loop of Figure 12 structure occupation efficiency be the structure of the pwm signal of α.Therefore, pwm signal is made of the comparison between the amplitude useful signal (modulation signal) that to be the carrier wave (in this case for sawtooth signal, but it also can be a triangular signal) of A represent with error E a by amplification.Carrier wave is used to be provided with chopping frequency.As long as modulation signal is on carrier wave, the pwm signal that is formed for the control set point of electric bridge 604 just presents positive pulse, otherwise it presents zero.Pwm signal is the reference signal (carrier signal) of fixing, and its pulse duration depends on error: be that the occupation efficiency of pwm signal makes electric current in can control load.This occupation efficiency has value

(that is, generator 603 will gain error E a that 1/A is applied to amplify so that obtain occupation efficiency α).

With reference to showing magnetization and Fig. 3 of two states of degaussing, occupation efficiency is that the pwm signal of α is applied in switch AL and BH, and with the pwm signal complementation, occupation efficiency is that the signal of 1-α is applied in switch AH and BL.Thereby, during magnetized state, dc voltage+U _DCBe applied in load duration curve α T, and during demagnetizing state, dc voltage-U _DCBe applied in load duration curve (1-α) T.So load 10 observed average voltages

Be (2 α-1) U _DCFigure 14 will be by the observed average voltage of load under the situation of all bifurcation regulating loops as shown in figure 12

Be expressed as the linear trend of the function of occupation efficiency α.

After having looked back prior art with regard to the bifurcation regulating loop, we will describe first embodiment that enables according to the regulating loop 700 of the four condition control circuit of the present invention that will realize with reference to Figure 15 now hereinafter.

Regulating loop 700 comprises:

-subtracter 701;

-amplifier 702;

-have a generator 703 of PWM (pulse width modulation) signal of occupation efficiency α;

-four-quadrant electric bridge in its just alternately state 705 or the negative alternating state 706 at it, is used for chopping voltage is offered load (being generally inductive load) 707, to the electric current I of its measurement _MesFormation will be by the electric current of described loop 700 lockings;

-control device 708 is used for just alternately 705 and negatively alternately change between 706.

Regulating loop 700 work are as follows: with current setpoint I _RefWith the measurement result I that wants blocked electric current _MesCompare.The current setpoint I that determines by subtracter 701 _RefWith the measurement result I that wants blocked electric current _MesBetween poor E be that the amplifier 702 of G amplifies by gain, with the poor Ea (gain G can be the combination of proportional gain, storage gain and the differential gain) that amplification is provided.The error E a that amplifies is compared with carrier wave (amplitude of being generally is triangular wave or the sawtooth signal of A), so that produce pwm signal via generator 703, its pulse duration is by the error modulation (α represents the occupation efficiency of pwm signal) of amplifying.It shall yet further be noted that the control of quadrant electric bridge is the function of the error between current setpoint and the current measurement result as in traditional PWM control.Difference is the PWM function, and bridge state depends on the symbol of being determined by pwm signal.

In practice, be used for just alternately 705 and the negative control device that alternately changes between 706 708 realize following state machines (shown in Figure 16):

-being in its just alternately 705 and occupation efficiency when eliminating when electric bridge, the variation of this state machine detected state and switch to alternately negative: the symbol arm switches.

-when electric bridge be in it negative alternately 705 and occupation efficiency when equaling 1, the variation of this state machine detected state and just switching to replaces: the symbol arm switches.

With reference to figure 8, during positive and negative replaced the two, occupation efficiency was that the pwm signal of α is applied in switch AL, and with the pwm signal complementation, occupation efficiency is applied in switch AH for the signal of (1-α).When electric bridge is in just replacing of it and occupation efficiency elimination, install the disconnection of 708 control switch BH and the closure of switch BL.On the contrary, when electric bridge be in it negative alternately and occupation efficiency when equaling 1, install the disconnection of 708 control switch BL and the closure of switch BH.

Advantageously, device 708 uses the mark signal of control character arm B and makes described arm to switch to negative alternately (can select minus symbol signal or nil symbol signal) from just replacing (plus sign signal).

According to electric bridge be in it just alternately or the negative transfer function of calculating electric bridge that replaces.

-just replace

Zero magnetized state: voltage+U _DCBe applied in load duration curve α T (wherein T represents the cycle of pwm signal);

Zero high afterflow state: no-voltage is applied in load duration curve (1-α) T.

Zero therefore, during just alternately, by the observed average voltage of load is ${\hat{V}}_L=\mathrm{\&alpha;}{U}_{\mathrm{DC}}.$

-alternately negative

Zero demagnetizing state: voltage-U _DCBe applied in load duration curve (1-α) T;

Zero low afterflow state: no-voltage is applied in load duration curve α T.

Zero therefore, during negative replacing, by the observed average voltage of load is ${\hat{V}}_L=-(1-\mathrm{\&alpha;})U_{\mathrm{DC}}.$

In other words, control circuit according to this embodiment of the invention comprises:

-be used for during this just replaces 705, will equaling product α * U _DCAverage voltage be applied to the device of load;

-be used for alternately will equaling product (α-1) * U during 706 negative _DCAverage voltage be applied to the device of load.

Figure 17 represents the transfer function of four-quadrant electric bridge, just under the situation of all bifurcation regulating loops as shown in figure 15 according to occupation efficiency α by the observed average voltage of load

Can clearly observe the linear behavior of average voltage in each replaces, and from one alternately to another switching that replaces (when occupation efficiency is eliminated when control circuit is in just alternately, perhaps control circuit be in negative alternately the time occupation efficiency equal at 1 o'clock).

The electric current I that Figure 18 to 21 will measure in different structure _Mes, current setpoint I _Ref, occupation efficiency be α pwm signal, make call sign arm B switch to the voltage V of the terminal of the mark signal of negative alternately (minus symbol signal) and load from just replacing (plus sign signal) _LBe expressed as the function of time.

With reference to Figure 18, when current setpoint descended suddenly, the difference between set point and the measurement result increased.This difference is born.Error is exaggerated.The occupation efficiency of pwm signal and this error is proportional reduces is up to its minimum value (0%).Because mark signal is positive (just replacing) when beginning, and because occupation efficiency is zero, so state machine detects state variation.Mark signal switches and becomes negative.The transfer function of Figure 17 is told us, and for zero occupation efficiency and minus symbol, the average voltage that puts on inductive load is negative and its amplitude maximum.The electric current of measuring reduces fast to restrain to set point.Along with the electric current of measuring near set point, error reduces and occupation efficiency increases, this amplitude that causes voltage reduces.

With reference to Figure 19, when current setpoint rose suddenly, the difference between set point and the measurement result increased.This difference is positive.Error is exaggerated.The proportional increase of the error of occupation efficiency and amplification and reach its maximum.Because mark signal is positive (just replacing) when beginning, and because occupation efficiency is maximum, so state machine does not detect any state variation.Thereby the voltage that puts on load reaches its maximum, and this makes electric current restrain to set point.The error of amplifying is along with the electric current of measuring reduces near set point.

With reference to Figure 20, when current setpoint rose suddenly, the difference between set point and the measurement result increased.This difference is positive.Error is exaggerated.Occupation efficiency and the proportional increase of this error and reach its maximum.It is maximum (100%) that state machine detects occupation efficiency, and this mark signal when beginning for negative.Mark signal switches and becomes positive.The positive voltage of the transfer function indication amplitude peak of the four-quadrant electric bridge of Figure 17.This voltage makes the electric current of measuring can increase and catch up with set point.Along with electric current near set point, error reduces, so occupation efficiency reduces.

With reference to Figure 21, when electric set point reduced suddenly, the difference between set point and the measurement result increased.This difference is born.Error is exaggerated.The proportional minimum value that reduces and reach it of the error of occupation efficiency and amplification.Because mark signal is negative when beginning, so state machine does not detect any variation.The average voltage for bearing that the transfer function indication of four-quadrant electric bridge applies, its amplitude is directly proportional with this error.The amplitude of the negative voltage between the terminal of inductive load will be maximum, and this causes that electric current reduces fast.Along with the electric current of measuring near set point, error reduces, so occupation efficiency increases again.The voltage that puts on load also reaches its maximum, and this makes electric current restrain to set point.The error of amplifying is along with the electric current of measuring reduces near set point.In this example, there is not sign change.

Under the situation of the solution that reference Figure 15 to 21 describes, static receiver error just alternately and negative be different between alternately.Thereby, in order between the terminal of load, to produce same average voltage

This error will replace under the situation different at two.

Situation about just replacing: $\mathrm{\&alpha;}=\frac{{\hat{V}}_L}{U_{\mathrm{DC}}}\&DoubleRightArrow;E_a^{+}=A\frac{{\hat{V}}_L}{U_{\mathrm{DC}}}$

Wherein

Specify the error that just replaces the amplification under the situation.

Bearing situation alternately: $\mathrm{\&alpha;}=1+\frac{{\hat{V}}_L}{U_{\mathrm{DC}}}\&DoubleRightArrow;E_a^{-}=A(1+\frac{{\hat{V}}_L}{U_{\mathrm{DC}}})$

Wherein Specify the error of the amplification under the negative alternately situation.

Therefore the ratio of error is $\frac{E_a^{-}}{E_a^{+}}=\frac{U_{\mathrm{DC}}+{\hat{V}}_L}{{\hat{V}}_L}.$

Therefore, Fu static receiver error can be greater than positive static receiver error.For example, if supply voltage is 49V and at the terminal place of load 1V is set that then ratio is 50.This causes discontinuous when regulating.From that time, between the tour between alternately the asynchronous of electric current taken place probably.But this main static receiver error can be offset by the increase of static gain.

Figure 22 illustrates and is used to second embodiment that realizes according to four condition control circuit of the present invention and be used to avoid the regulating loop 800 of this static receiver error problem.

Regulating loop 800 comprises:

-subtracter 801;

-amplifier 802;

-have a generator 803 of PWM (pulse width modulation) signal of occupation efficiency α;

-transducer 809, be used for occupation efficiency be the pwm signal of α be converted to the pwm signal that occupation efficiency is α ' (and be used to provide with occupation efficiency be that the occupation efficiency of the pwm signal complementation of α ' is

Pwm signal);

-four-quadrant electric bridge in its just alternately state 805 or the negative alternating state 806 at it, is used for chopping voltage is offered load (being generally inductive load) 807, to the electric current I of its measurement _MesFormation will be by the electric current of described loop 800 lockings;

-control device 808 is used for just alternately 805 and negatively alternately switch between 806.

Regulating loop 800 work are as follows: with current setpoint I _RefWith the measurement result I that wants blocked electric current _MesCompare.The current setpoint I that determines by subtracter 801 _RefWith the measurement result I that wants blocked electric current _MesBetween poor E be that the amplifier 802 of G amplifies by gain, with the poor Ea (gain G can be the combination of proportional gain, storage gain and the differential gain) that amplification is provided.The error E a that amplifies is compared with carrier wave (amplitude of being generally is triangular wave or the sawtooth signal of A), so that produce pwm signal via generator 803, its pulse duration is by the error modulation (α represents the occupation efficiency of pwm signal) of amplifying.

Occupation efficiency is that the pwm signal of α is changed to obtain another pwm signal of same frequency by transducer 809, and its occupation efficiency α ' equals | 2 α-1|.

Transducer 809 comprises the device of the subtraction between pwm signal that for example is used to carry out 50% occupation efficiency and the pwm signal that occupation efficiency is α.The pwm signal that obtains has occupation efficiency

This subtraction can be obtained by XOR function as shown in figure 23.The input of this XOR function is respectively that to have the synchronous pwm signal and the occupation efficiency of 50% occupation efficiency be the pwm signal of α, and directly obtains occupation efficiency at output and be Pwm signal.

Transducer 809 also comprise be used for to occupation efficiency be

The device that doubles of pwm signal; In other words, consequential signal is that pulse duration is the big pwm signal of twice.Therefore occupation efficiency is | 2 α-1|.At last, transducer 809 with occupation efficiency be the pwm signal of α be converted to occupation efficiency be α '=| the pwm signal of the same frequency of 2 α-1|.

These devices that are used for pwm signal is doubled can use two counters to realize.The use of these counters as shown in figure 24.

From occupation efficiency is the signal of the processing of (α-1/2), and on the rising edge of the signal of handling, consequential signal (signal that doubles) changes high state into, and is increased progressively then during pulse duration by first counter of clock control (pace) and to stop.On trailing edge, second counter increases progressively (by the clock constant speed identical with first counter): when the value of this second counter equaled the value of first counter, consequential signal was eliminated.Consequential signal has the big pulse duration of pulse duration twice of the signal of processing.

Be used for just alternately 805 and the negative control device that alternately switches between 806 808 realize following state machines (shown in Figure 25):

-when electric bridge be in it just alternately 805 and occupation efficiency strictly less than 50% the time, this state machine detects the variation of state and switches to alternately negative: the symbol arm switches.

-when electric bridge be in it negative alternately 806 and occupation efficiency more than or equal to 50% the time, this state machine detects the variation of state and just switches to and replaces: the symbol arm switches.

With reference to figure 8, during just alternately (α is more than or equal to 50%), occupation efficiency is that the pwm signal of α ' is applied in switch AL, and occupation efficiency is applied in switch AH for the pwm signal of the complementation of (1-α ').

Negative alternately during (the α strictness is less than 50%), occupation efficiency is that the pwm signal of 1-α ' is applied in switch AL, and occupation efficiency is that the pwm signal of the complementation of α ' is applied in switch AH.

When electric bridge be in it just alternately and occupation efficiency α strictness less than 50% the time, install the disconnection of 808 control switch BH and the closure of switch BL.On the contrary, when electric bridge be in it negative alternately and occupation efficiency α more than or equal to 50% the time, install the disconnection of 808 control switch BL and the closure of switch BH.

Advantageously, device 808 uses mark signals to come by making described arm to switch to negative alternately (can select minus symbol signal or nil symbol signal) and come control character arm B from just replacing (plus sign signal).

According to it be in it just alternately or the negative transfer function of calculating electric bridge that replaces.

-just replace:

Zero magnetized state: bus voltage+U _DCBe applied in load duration curve α ' T;

Zero high afterflow state: no-voltage is applied in load duration curve (1-α ') T;

Zero therefore, by the observed average voltage of load is ${\hat{V}}_L={\mathrm{\&alpha;}}^{\&prime;}{U}_{\mathrm{DC}}=(2\mathrm{\&alpha;}-1)U_{\mathrm{DC}};$

-alternately negative:

Zero magnetized state: bus voltage-U _DCBe applied in load duration curve (1-2 α) T;

Zero low afterflow state: no-voltage is applied in load duration curve 2 α T;

Zero therefore, by the observed average voltage of load is ${\hat{V}}_L=-(1-2\mathrm{\&alpha;})U_{\mathrm{DC}}=(2\mathrm{\&alpha;}-1)U_{\mathrm{DC}}.$

In other words, control circuit according to this embodiment of the invention comprises and is used for just alternately alternately will equaling product (2 α-1) * U during 806 during 805 and negative _DCAverage voltage put on the device of load.

Figure 26 illustrates the transfer function of four-quadrant electric bridge, just under the situation of all four condition regulating loops as shown in figure 22 according to occupation efficiency by the observed average voltage of load Can clearly observe the linear behavior of average voltage: except that the fact of the conversion that produces occupation efficiency α, this transfer function is identical with the transfer function of the control of known bifurcation four-quadrant electric bridge.Be understood that by its symmetry, this transfer function makes it possible to solve the static receiver error problem.

Realize control strategy various control device (under using according to the situation of the control circuit of the regulating loop of Figure 15 and using according under the situation of the control circuit of the regulating loop of Figure 22 the two) be the logic device of for example incorporating among the FPGA (field programmable gate array).

Obviously, the present invention is not limited to the embodiment that has just described.

It should be noted that be applied to have described the present invention under the situation of electromagnetic valve actuator, but it also is applied to the motor by any kind of of inductive load control such as motor.

Be applied under the situation of motor, described machine can be single-phase or three-phase.

In addition, the embodiment of description relates to the control of electric current in the inductive load, but the present invention obviously is applicable to the control of the voltage between the terminal of described load.

In addition, we have described wherein with the application of FPGA programming with the realization state machine; Also can realize this state machine by using hard wired logic.

Note, under the situation of using mosfet transistor, specifically described the present invention; Also can use the transistor (for example IGBT) of other type and not break away from framework of the present invention.

At last, any device can be substituted by equivalent device.

Claims (17)

1. the circuit (100,200,300,400,600,700) of the voltage between the terminal of an electric current that is used for controlling electric control unit (110) or described electric control unit, described circuit comprises:

-electric bridge has four terminals (105,106,107,108) and comprises four control switchs (AH, AL, BH, BL),

-be used for the power supply (109) of described electric bridge,

-utilize pulse width modulation to control the device of at least two switches in described four switches,

Described power supply (109) is connected between the first terminal (105) and second terminal (106) of described electric bridge,

Described electric control unit (110) is connected between the 3rd terminal (107) and the 4th terminal (108) of described electric bridge,

First switch (AH) is connected between the described the first terminal (105) and described the 3rd terminal (107) of described electric bridge,

Second switch (BH) is connected between the described the first terminal (105) and described the 4th terminal (108) of described electric bridge,

The 3rd switch (AL) is connected between described the 3rd terminal (107) and described second terminal (106) of described electric bridge,

The 4th switch (BL) is connected between described the 4th terminal (108) and described second terminal (106) of described electric bridge,

Described control circuit is characterised in that it presents:

-the first state, wherein said first switch (AH) and the 4th switch (BL) closure, and described second switch (BH) and the 3rd switch (AL) disconnection,

-the second state, wherein said second switch (BH) and the 3rd switch (AL) closure, and described first switch (AH) and the 4th switch (BL) disconnection,

In-following two states at least one:

Zero third state, wherein said the 3rd switch (AL) and the 4th switch (BL) closure, and described first switch (AH) and second switch (BH) disconnection,

Zero four condition, wherein said first switch (AH) and second switch (BH) closure, and described the 3rd switch (AL) and the 4th switch (BL) disconnection;

The mandate of described pulse width modulation control device:

-from described first state to the described the 3rd or four condition the transformation of at least one state,

-from described second state to the described the 3rd or four condition the transformation of at least one state,

-from the described the 3rd or four condition at least one state to the transformation of described first state,

-from the described the 3rd or four condition at least one state to the transformation of described second state.

2. as the described control circuit of last claim (300,400,600,700), it is characterized in that the mandate of described pulse width modulation control device:

-the first so-called negative alternating phases, comprise transformation and transformation from the described third state to described first state from described first state to the described third state, described first switch (AH) and the 3rd switch (AL) form the first arm, be called amplitude arm (A), switch with so-called chopping frequency, and described second switch (BH) and the 4th switch (BL) formation second arm, symbol arm (B) be called, described second switch (BH) and the 4th switch (BL) be closed and disconnected respectively

-the second so-called just alternately stage, comprise transformation and transformation from described four condition to described second state from described second state to described four condition, described first switch (AH) and the 3rd switch (AL) switch with described so-called chopping frequency, and described second switch (BH) and the 4th switch (BL) disconnect respectively and closure

The described second switch (BH) of described symbol arm (B) and the switching of the 4th switch (BL) are guaranteed to change described bearing alternately and just alternately with the frequency that is lower than described chopping frequency.

3. as the described control circuit of last claim (400), it is characterized in that it comprises the bypassed resistor (201) that is connected in series between described electric control unit (110) and described the 4th terminal (108).

4. as the described control circuit of last claim (400), it is characterized in that it comprises operational amplifier (202), the terminal of described bypassed resistor (201) forms the inverting input and the in-phase input end of described operational amplifier.

5. as a described control circuit in the claim 2 to 4, it is characterized in that it comprises:

-charge pump capacitor (503), when being recharged, it is suitable for carrying the control voltage that is used for described second switch (BH);

-second source (501) is carried the voltage less than the voltage of being carried by described first voltage source, and described second voltage source is applicable to when described the 4th switch (BL) is closed to be described charge pump capacitor charging;

-be used for when described control circuit just is in stage alternately, forcing transformation so that the device that described charge pump capacitor is recharged via described second source from described four condition to the described third state.

6. as the described control circuit (700) in the claim 2 to 5, it is characterized in that described control device comprises:

-be used to produce the device (701,702,703) of pulse width modulating signal with occupation efficiency α;

-be used for described that to have occupation efficiency be that the pulse width modulating signal of α is applied to described the 3rd switch (AL) and will has occupation efficiency is the device (705,706) that the pulse width modulating signal of 1-α is applied to described first switch (AH);

-be used for just alternately and negative alternately between the device (708) of turnover to realize following state machine:

Zero when described electric bridge be in it just alternately and occupation efficiency α when being eliminated, this state machine detect state variation and change into alternately negative,

Zero when described electric bridge be in it negative alternately and occupation efficiency α when equaling 100%, this state machine detects state variation and just changes into and replaces.

7. as the described control circuit of last claim (700), it is characterized in that described power delivery dc voltage+U _DC, described control circuit comprises:

-be used for will equaling product α * U during just alternately described _DCAverage voltage be applied to the device (705) of described electric control unit;

-be used for during described negative replacing, will equaling product (α-1) * U _DCAverage voltage be applied to the device (706) of described electric control unit;

8. as the described control circuit (800) in the claim 2 to 5, it is characterized in that described control device comprises:

-be used to produce the device (801,802,803) of pulse width modulating signal with occupation efficiency α;

-be used for described pulse width modulating signal with occupation efficiency α is converted to have occupation efficiency α '=| the device of the pulse width modulating signal of 2 α-1| (809);

-be used for described that to have occupation efficiency be that the pulse width modulating signal of α ' is applied to described the 3rd switch (AL) and will has occupation efficiency is the device (805) that the pulse width modulating signal of 1-α ' is applied to described first switch (AH) with described during just alternately;

-be used for described that negative to have occupation efficiency be that the pulse width modulating signal of 1-α ' is applied to described the 3rd switch (AL) and will has occupation efficiency is the device (806) that the pulse width modulating signal of α ' is applied to described first switch (AH) with described during alternately;

-be used for just alternately and negative alternately between the device (808) of turnover to realize following state machine:

Zero when described electric bridge be in it just alternately and described occupation efficiency α strictness less than 50% the time, described state machine detected state changes and changes into alternately negative.

Zero when described electric bridge be in it negative alternately and described occupation efficiency α more than or equal to 50% the time, described state machine detected state changes and just changes into and replaces.

9. as the described control circuit of last claim (800), it is characterized in that described power delivery dc voltage+U _DC, described control circuit comprise be used for described just alternately during and negatively will equal product (2 α-1) * U during alternately described _DCAverage voltage be applied to the device of described electric control unit.

10. as a described control circuit in claim 7 or 8, it is characterized in that, described be used for described pulse width modulating signal with occupation efficiency α is converted to have occupation efficiency α '=| the device of the pulse width modulating signal of 2 α-1| comprises:

-be used to carry out the device that occupation efficiency equals the subtraction between the described signal that 50% signal and occupation efficiency be α;

-be used for the device that will double by the signal that described subtraction obtains.

11. as the described control circuit of last claim, it is characterized in that, described to be used to carry out the device that occupation efficiency equals the subtraction between the signal that 50% signal and described occupation efficiency be α be the device of carrying out the XOR function, and having described occupation efficiency on its two inputs respectively, to equal 50% signal and described occupation efficiency be the signal of α.

12. a described control circuit as in claim 10 or 11 is characterized in that, the device that the described signal that is used for being obtained by described subtraction doubles comprises at least one counter.

13. a described control circuit in the claim is characterized in that described control device is included in the Programmable Logic Device as described above.

14. a described control circuit in the claim is characterized in that described switch is a mosfet transistor as described above.

15. the purposes of a described control circuit in the electric parts that form by inductive load in the claim as described above with variable inductance.

16., it is characterized in that described electric parts are included in to have in the actuator that activates part as the described purposes of last claim, described electric parts are controlled described actuating part with displacement mode.

17., it is characterized in that described actuator is the electromagnetic valve actuator that is used for motor vehicles as the described purposes of last claim.

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